On Fri, 11 Oct 2002 18:32:11 -0400, "Ted Jones" <sirbooli at comcast.net>
wrote:
> i was wondering if there was a standardized chart for bacteria/DH5a OD600
>with corresponding cell concentration (x cells/ml). can i use the one for
>haploid yeast. yes i know there is a hard way by serial dilutions and ect
>but i just wanted to know if there was anything published and readily
>availiable.
>>
Any such conversion is simply an approximation. The conversion ratio
depends on the organism, the growth conditions, and even the stage of
growth. That is, it varies during a growth cycle -- especially as the
cells leave and enter the non-growing phase (and change size).
Using OD is convenient, and reproducible under given conditions. If
you really need to know cells, then measure cells (viable or particle
count). If you just need some rough estimate, then you can measure one
conversion, or at your own risk use one someone else has measured for
something.
bob
posted/emailed